Get your moose mugs ready! It's time to watch National Lampoon's Christmas Vacation on a loop for the rest of the year. It's been 25 years since Clark Griswold and his family lit up the holiday scene – we're traveling back (in our station wagon) to 1989 when ET was invited on set for the holiday classic.

The third installment of the Vacation series stars Chevy Chase and Beverly D'Angelo reprising their roles as Clark and Ellen Griswold, and their ever changing children (this time Juliette Lewis and Johnny Galecki) as Russ and Audrey.

Instead of heading to Wally World or Europe, the family is staying at home to fulfill Clark's hopes of having a good old fashioned family Christmas.

"When I originally entertained the idea of doing another Vacation movie I thought, 'What would be the best thing, the closest to what we do in our family?' and what we do every year is, we have, at Christmas time, everybody over our house who's part of the family," Chevy Chase told ET on set. "If you know Clark Griswold -- everything that can go wrong does."

From picking out a tree, to lighting the house, to getting enrolled in a 'jelly of the month club,' nothing goes quite right for incurable optimist Clark Griswold.

"How much sap and junk do you get on yourself? How easy is it to get the lights working? How tough is it to get the tree the right height? All those little things that you never think about," said Chevy. "You always think, 'oh, we'll put the tree in, we'll put the bulbs on, and we'll light it up!' That in itself is an adventure. That's like, Indy Jones! That's tough stuff."

"I think that the thing about the Griswold's is they always end up having the experiences that so many other people have," Beverly D'Angelo told ET on set. "I think there's a bit of everybody's Christmas in Christmas Vacation."

Check out this video for a trip down memory lane with this Christmas classic!